Prenatal Diagnosis of Intragenic <i>HNF1B</i> Variant-Associated Renal Disease by Exome Sequencing

Abstract

<b><i>Introduction:</i></b> <i>HNF1B</i>-associated diseases are a group of genetic conditions that affect the kidney as well as other organ systems. Kidney anomalies are the most common symptoms. Other defects may include early-onset diabetes, genital abnormalities, and abnormalities of pancreas and liver function. Renal involvement has emerged as the earliest finding in <i>HNF1B</i> disease, even in prenatal life, with the most common feature being hyperechogenic kidneys. <b><i>Case Presentation:</i></b> In this study, we present 3 fetuses with bilateral renal hyperechogenicity identified by ultrasound in the second trimester. No pathogenic copy number variations were revealed by amniocentesis with chromosomal microarray analysis (CMA). Heterozygous variants in <i>HNF1B</i> were detected in all 3 fetuses by further investigation with exome sequencing (ES). Two pregnancies were terminated, and one was continued to term. <b><i>Discussion and Conclusion:</i></b> Because of the known high frequency of <i>HNF1B</i> aberrations in fetal hyperechogenic kidneys, <i>HNF1B</i> screening should be an integral part of prenatal diagnosis for such fetuses. ES should be recommended following or concurrently with CMA for rapid prenatal detection. The ES results would improve the diagnostic yield and are beneficial in guiding counseling and management.